1. Field
Embodiments relate to an auto-focusing apparatus.
2. Description of the Related Art
There are related-art methods of previously obtaining a target position of a focus lens by using a phase difference Automatic Focusing (AF) module and of performing lens driving during a release time lag so as to focus on a subject (moving object) that moves in a direction of an optical axis of a camera (U.S. Pat. No. 5,005,039, U.S. Pat. No. 5,196,881, and U.S. Pat. No. 5,434,638). Focusing can also be performed by using the methods even when a moving subject (moving object) is photographed.
In contrast AF type cameras using an imaging device, a peak of focus evaluation values is detected, and a target position of a focus lens corresponding to the peak is detected. Thus, the target position cannot be previously predicted. In contrast AF type cameras using an image device, the target position of the focus lens cannot be previously obtained, and it takes time to detect the peak of the focus evaluation values. Thus, it is not easy to focus on the moving object. JP 2009-012174 discloses a method of predicting a target position of a focus lens with respect to a moving object by using focus evaluation values even in contrast AF type cameras. However, the method disclosed in JP 2009-012174 does not consider backlash compensation driving. Thus, focusing is not substantially performed, and there is no reality. In addition, functions of shutter or diaphragm control are not considered with respect to the moving object during a release time lag, and there is no function of compensating for the release time lag of a camera.